Manufacture of alloys of silicon.



HANs 'eoLnsoHMID'r, or EssENnNnnmUHR, GERMANY.

Mama-momma or ALLoYs omsxnrcon.

I Specification of Letters Patent.

' Patented March 16, 1909.

I Application filed April 24, 1908. Serial No. 428,938.

To all whom it may concern:

Be it known that I, HANS GOLDSOHMIDT, a subject of the King of Prussia, German Em-. peror, and resident of Essen-on-the-Ruhr, in the German Empire, have invented certain new and useful Improvements in the Manufacture of Alloys of Silicon, of which the following is an exact specification.

This invention relates to the manufacture of alloys of silicon and one of the alkaline earth metals calcium, barium or strontium. It has already been proposed on a laboratory scale to heat silicon and lime together in an electric furnace so as to produce a calcium siliconcompound. In these experiments carried out by Moissan the reaction took place in the presence of carbon which doubtless had some effect on the reaction. Moissan comes to the conclusion that with an excess of lime in the mixture, a silicate of limeis formed in the furnace and not a calcium silicon alloy.

The object oiv the presentinvention is to produce a calcium silicon alloy or an alloy of silicon with barium or strontium free from carbon and in a commercially practical manner.

The invention consists in a process for manufacturing alloys of silicon with the alkaline metals calcium, barium or strontium by heating silicon or ferro-silicon in an electric furnace with an excess by weight of the oxid of calcium barium or strontium or salts of the same containing the oxids and decomposable by heat at ordinary furnace temperatures, saidheating within the electric furnace being carried out in the presence of a flux, for the purpose of roducin an easily crumbling slag from w 'ch particles orlight grains of the alloy may be separated by screening. 40 In practice I have found that good results may be obtained by heating a mixture of two parts by weight of lime with one part by weight of silicon together with a flux in an electric furnace. Inthis way ,there is obtained a calcium-silicon alloy of about 40 parts by weight of calcium and 60 parts by weight of silicon, if a' ractically pure silicon is used. Instead of s' icon, ferro-silicon may be used and further instead of lime carbonate of lime or anysalt'of calcium which produces lime when being heated may be used. The alloys of calcium and silicon hitherto a calcium-silicon alloy free from carbon and 4 containing up to about 40 per cent. of calciur n is easily to be obtained by carrying out this process.

As I have mentioned above the addition of the flux is necessary to producea slag which vcrumbles when getting cold instead of form-.

ing a solid slag. In this way the output is greater and nearly a complete one-because the light grains of alloy can be separated from the slag by screening. A'convenient' flux to use is fluorid of calcium (fiuor spar) which may be mixed with chlorid of calcium in the proportions of 15 parts of fluorid of calcium to 5-10 parts of chlorid of calcium and this mixture maybe added to 100 parts of the above mentioned mixture of lime and silicon. The commencement of the reaction in the mass is indicated by the sinking down of the same.

It will be understood that instead of lime and lime compounds, barium or strontium com ounds which produce the oxids of these alkaiine earth metals when heated in a furnace to an ordinary temperature, may be used for the purpose of obtaining the corresponding alloys of the same with silicon under addition of a flux.

Having thus fully described the nature of my said invention what I desire to secure by Letters Patent of the United States is:-

1. Process for producing an alloy of silicon with an alkaline earth metal consisting in heating silicon or ferro-silicon with an excess of an oxid of the alkaline metal in an electric furnace in resence of a flux producing a crumbling s ag.

2. Process for producing an alloy of silicon .with calcium conslsting in heatin silicon or 4. Process for producing an alloy of silicon with lime in the proportions 1 to 2 in an elecwith calcium Consisting 1n heating silicon or tric furnace in presence of a flux composed of ferro-silicon with an excess of lime in an elecfluor spar and calcium chlorid.

trio furnace in presence of a flux composed of HANS GOLDSCHMIDT. 5 fiuor s ar and calcium chlorid. Witnesses:

i rocess for producing an alloy of silicon L. M. WOHLGEMUTH,

with calcium consisting in heating silicon E. ALDENDORFF. 

